Centrifugal speed control for vacuum cleaners



March 4, 1952 SNYDER 2,588,301

CENTRIFUGAL SPEED CONTROL FOR VACUUM CLEANERS Filed April 22, 1946 2 SHEETSSHEET 1 March 4, 1952 L. H. SNYDER 2,588,301

CENTRIFUGAL SPEED CONTRQL FOR VACUUM CLEANERS filed Appil 22, 1946 2 SHEETS-SHEET 2 Patented Mar. 4, 1952 CENTRIFUGAL SPEED CONTROL FOR vacuum CLEANERS Leland H. Snyder, Chicago, Ill., assignor, by mesne -M0narch Company, St. on of Delaware Application April 22, 1946, Serial No. 664,135

assignments, to Knapp Louis, Mo., acorporati 1 Claim. 1

This invention relates to a vacuum cleaner and particularly to a mechanism permitting selective manual variation of the intensit of the air current produced by the fan of the vacuum cleaner.

It has long been recognized in the art that some 5 vacuum attachments to provide a suction current of air for cleaning of upholstered furniture, drapes, Venetian blinds, etc. Obviously, for cleaning of rugs having a heavy nap it is desirable to utilize the maximum intensity of air stream which the fan and motor of the vacuum cleaner can develop; however, such maximum intensity air stream is much in excess of the desirable intensity when cleaning rugs having a shorter nap of floor rugs of the so-called throw rug variety. Likewise, when the cleaner is converted for use 2 with vacuum attachments, the intensity of the suction air stream desired varies greatly with the use to which the cleaning attachments are put. A very strong intensity air stream might be desirable for cleaning radiators but would actually be harmful if applied to the cleaning of drapes or delicate curtains. While vacuum cleaners have heretofore been known in the art which incorporated a control circuit permitting the selection of two or three different speeds of operation, such arrangements utilize electrical interconnections of a plurality of windings oi the motor, which had to be specially wound to permit such speed con trol to be obtained. Furthermore, the resultingelectrical connections and switches required to effectuate speed control in such manner were complicated and expensive.

Accordingly, it is an object of this invention to provide an improved vacuum cleaner construction and particularly an improved speed control arrangement for the motor driven fan of a vacuum cleaner by which the intensity of air current produced by the fan may be conveniently manually adjusted over a wide range.

A further object of this invention is to provide :6

an improved speed control for a motor driven fan of a vacuum cleaner incorporating a mechanically adjustable centrifugal switch which eliminates the necessity for special windings on the motor or complicated electrical switching arrangements to efie'ctuate the speed control of the motor.

A particular object of this invention is to pro- .vlde an improved variable speed control for a vacuum cleaner wherein the manual control knob is conveniently located at the end of the handle n of the vacuum cleaner and the mechanical connection between such control knob and the speed regulating mechanism is housed within the hollow handle.

The specific nature of the invention as well as other objects and advantages thereof will become apparent to those skilled inthe art from the following detailed description of the annexed sheets of drawings which, by way of preferred example only, illustrate two specific embodiments of the invention.

On the drawings:

Figure 1 is an elevational view, partly in section, of a vacuum cleaner casing embodying a speed regulating device constructed in accordance with this invention.

Figure 2 is an. elevational view of the centrifugally operated electric switch utilized in the construction of Figure 1; U

Figure 3 is an electric circuit diagram showing the connection of the contacts of the centrifugal switch relative to the motor armature and windmg;

Figure 4 is an elevational view of a modification of this invention wherein the manual control member for the speed adjusting mechanism is located on the handle;

Figure 5 is a partial sectional view, of Figure 4 illustrating the speed regulating mechanism;

Figure 6 is a partial sectional view of the upper portion oithe handle of the vacuum of Figure 4.

Figure '7 is a detail view, partially in section, showing the speed regulating mechanism of Figure 5.

As shown on the drawings:

Referring to Figure 1, there is shown a vacuum cleaner construction comprising a hollow casing 2 which is movably supported on a floor or rug surface by a plurality of wheels 4. Casing 2 is divided by a transverse partition 6 into a forward fan chamber 8 and a rearward motor chamber ii). A motor i2 is suitably mounted in motor chamber lo and may comprise any conventional form of motor such as a so-called universal type commutator motor. Motor shaft ['4 projects for wardly into fan chamber 8 and a suitable fan I6 is mounted thereon.

The structural details thus far described form no part of this invention and for description in greater detail; reference may be had to my copending joint application with Robert F. Lindgren, Serial No. 6841718, filed July 19, 1946, now abandoned. As ismore fully described in my copending application, a suitable opening is pro-' videdin the front wall of fan chamber 8 to selec .lating unit similar to that tively accommodate a hose coupling I8 by which the vacuum cleaner fan may be utilized to operate any one of a plurality of well known vacuum attachments. Of course, when the hose coupling I8 is removed from its connection with fan chamber 8 the air stream developed by fan I6 is drawn upwardly from the floor or rug immediately below the forward portion of the casing 2 in conventional manner. In either event, the intensity of the air stream produced by the fan I6 may be readily controlled by controlling the speed of rotation imparted to the fan I6 by the motor I2.

To accomplish a manual control of the speed of motor I2 a centrifugally operating electrical switch unit 20 is assembled to the rear end of the motor shaft I4. Centrifugal switch 20 may comprise any one of several well known forms of such switches which operate to open their contacts at a speed which is determined by the positionjof an adjusting member, but preferably the centrifugal switch unit 20 comprises a speed regushown and described in U. S. Patent No. 1,7 67,146, issued June 24, 1 0, to Royal Lee. As is more fully described in the above referred to Lee patent, the centrifugal switch unit 28 comprises an insulating disk 32 upon which are mounted a pair of switch blades 22 each carrying switch contacts 24 which are arranged to separate at a predetermined rotational speed dependent upon the restraining force imparted to one of the switch blades by an adjusting member 26. Adjusting member 26 is pivoted to the disk 32 and provided with a ball-like portion :21 which is disposed substantially at the rotational axis of the centrifugal switch 20 and connected through a link connection 28 with one of the switch blades 22. Hence, a variation of the axial position of the ball portion 21 of the adjusting member 26 will produce a variation in the speed at which the contacts 24' of the centrifugal switch unit 20 open. On the other side of disk 32 a pair of slip rings 34 are provided by which electrical connections are made with the switch contacts 24 through the respective cooperation of a pair of brushes 35 with such slip rings.

While the specific wires accomplishing the electrical interconnection of the centrifugal switch 20 with the motor I2 are not shown in Figure l, the electrical circuit is preferably arranged as shown in Figure 3. Thus the motor I2 is adapted to be connected to a source of power through a primary ofi-on switch 40 which may be located at any convenient place onthe carpet sweeper and a series connection is effected between the field coils 42 of the motor, the armature 44 and the contacts 24 of switch 20. Preferably a resistor 46 and condenser 48 are connected in Parallel to the. contacts 24. It is therefore apparent that the opening of the contacts 24 produces a reduction in the voltage applied to the armature of motor I2 .due to the voltage drop across resistor 46 and accordingly the speed of such motor is reduced to a point where the contacts 24 again close. Hence the speed of motor I2 and fan I6 is determined by the particular setting of the adjustable member 26 of the centrifugal switch unit 20.

In accordance with this invention, the adjustable member 26 is manually controlled from the exterior of the casing 2. In the modification illustrated in Figure 1, a bell crank lever 56 is medially pivoted on pin 52 on the inside of easing 2 and the one arm 54 of the lever 58 engages the adjustable member 26 to position such member at any one of a plurality of points along the axis of shaft I4. The other arm 56 of lever 50 engaged by a manually operable cam 58. Cam 58 comprises a disk-like member having an eccentric peripheral surface 60 and cam 58 is rigidly secured to a hub 62 which is rotatably journalled in the side wall of casing 2. Since the casing 2 is a relatively thin walled member, it is preferable to provide a hOllOW bushing 64 which has a head portion 66 complementarily shaped to conform to the exterior of casing 2 and a shank portion 68 which projects into the interior of casing 2 through a suitable aperture. Bushing 64 is secured to the side wall of casing 2 by any suitable means such for example as by the annular plate III and the screws I2. A manual operating knob I4 is secured to the outwardly projecting end of hub 62 and provides a convenient means by which the rotative position of cam 58 may be manually adjusted. Obviously, rotation of cam 58 produces a displacement of adjusting member 26 of the centrifugal switch unit 28 thereby controlling the speed of the motor I2 and fan I6.

Referring now to Figures 4 through 6, wherein identical numerals refer to similar parts as in the above described modification, a modification of this invention is shown wherein the manually operable knob for adjusting the rotative position of the speed controlling cam 58 is mounted on the end of the hollow handle16. Handle I6 is pivotally secured at its bottom portion to the sweeper casing 2 in conventional manner. A motor I2, fan I6, centrifugal switch unit 20, lever 50 and speed controlling cam 58 are provided within the casing 2 and are identicalv with corresponding elements already described in connection with the modification of Figure 1.

The handle I6 comprises a hollow tubular member which extends from the casing 2 ma generally upstanding direction and in the upper end of handle I6 a manual control knob I8 is rotatably journalled on an integral hub portion 80. Control knob I8 is secured in assembled relationship to the handle I6 by means of a spring ring 82 which in the assembled position, lies partly in an annular exterior groove 84 provided on the hub portion of operating knob 78 and an annular interior groove 85 provided in the handle '16.

To effect a driving connection between operating knob I8 and the hub 62 upon which speed adjusting cam 58 is mounted, a mechanical connection is provided between hub 62 and operating knob 18 which preferably comprises a flexible shaft element 86. Flexible shaft 86 is disposed throughout the major portion of its length within the bore of the hollow handle I6 and at its upper end projects into a suitable axial recess 88 in the operating knob I8 and is rigidly secured therein by a set screw 80. At its lower end, fiexible shaft 86 projects out of a suitable aperture (not shown) in the side wall of handle I6 and is inserted in an axial opening 92 provided in the hub 62. The inserted end of flexible shaft 86 is rigidly secured to hub 62 by a set screw 94 which also secures a ring element 96 to the hub 62 to prevent axial displacement of the hub 62 and cam 58 relative to the bushing 64 in which the hub 62 is rotatably journalled.

The operation of this modification is identical to that already described in connection with the modification of Figure 1. The operator need only rotate the operating knob I8 to produce adesired variation in the speed of the motor I2 and fan I6 to adjust the intensity of the air current produced by the fan I6 to that value which is most suitable for the particular cleaning operation being accomplished.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claim.

I claim as my invention:

In a vacuum cleaner, a casing, a fan in said casing, a motor in said casing driving said fan, a hollow upstanding handle connected to said casing, said fan being rigidly attached to the rotatable shaft of said motor, a centrifugally operated electric switch driven by said motor, an adjusting member on said switch axially movable to adjust the speed at which said centrifugal switch opens, means connecting said switch in the energization circuit of said motor, whereby the opening of said switch reduces the speed of said motor, cam means rotatably journalled in said casing and adjustably engageable with said adjusting member axially to control the speed of said motor, a manually operable control knob rotatably journalled on said handle, and a flexible shaft disposed in said hollow handle and connecting said knob and said cam means, whereby manual rotation of said knob rotates said shaft and said cam means to selectively vary the intensity of the air current produced by said fan.

LELAND H. SNYDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,447,814 Paulus Mar. 6, 1923 1,767,146 Lee June 24, 1930 2,040,188 Smellie May 12, 1936 2,064,388 Smellie Dec. 15, 1936 2,099,050 Chamberlain Nov. 16, 1937 2,161,344 Fuller June 6, 1939 2,213,191 Johnston Apr. 3, 1940 2,241,528 Strauss et al. May 13, 1941 2,274,480 Jepson Feb. 24, 1942 

